For additional resources, you may utilize the Power & Communications Division Page on the Plastic Pipe Institute (PPI) website.
1. How do I couple polyethylene?
Petroflex has a variety of coupling methods, each designed for the type of installation being performed. E-Loc® couplings are high-strength metal or Polyurethane couplings for plowing. E-Lok® couplings provide a non-metallic, non-conductive coupling for trench installations. Left/right threaded aluminum couplings install easily with a common pipe wrench. Tri-plex and multi-stage end caps are also available for sealing the wire inside conduit. Double E-Loc® couplings are reusable and are constructed similar to a compression coupling. Double E-Loc® can maintain pressures over 200 psi, even when unrestrained.
3. Does Petroflex’s polyethylene conduit come in different colors?
Yes, Petroflex can supply a variety of colors. We do recommend black, due to its superior UV resistance and economy. Standard colors are black, gray, red, orange, white, blue, green, yellow and terra cotta. A method to economically color code duct and conduit is by striping. Petroflex can extrude 3 stripes into the outer wall of the conduit. These stripes become an integral part of the conduit and the exterior wall remains smooth and concentric. We can stripe the conduit in any of our nine standard colors. And don’t forget that custom colors are always available for solid color and striped conduit. (Min quantities may apply)
4. Does Petroflex provide sequential marking for their conduit?
Yes, we do! All pipe is marked every two feet. Heat indent (please specify if required) and inkjet print, you may add your company name, lightning bolt, or other required markings at no additional cost (Custom orders are non-returnable)
6. How much pull can be exerted on polyethylene?
Just check the Ultimate Tensile Strength Chart in our Petroflex Product Manual. Here is just one example: Our six inch conduit with an outside diameter of 6.625 inches, and a Schedule 40 inside diameter has a tensile strength of 18,000 pounds. Try the Conduit Design Calculator to find the best wall thickness for your bore.
7. What can I do to maximize my pulls?
For the most efficient pull, the conduit should be laid straight and level. Even though polyethylene gives you great flexibility, using a good cable lubricant ensures longer, easier pulls.
8. What kind of cable lubricant should be used with polyethylene?
Petroflex’s ProPull™ cable lubricant is the best choice for making long pulls smooth. ProPull™ Lube is a nontoxic polymer gel that clings to polyethylene cable jackets and conduit, and carries the lube far into the conduit. ProPull™ Lube doesn’t contain silicone, so it won’t harm cable or other sheath material. Petroflex’s Product Manual and this website contain a Lube Quantities Chart which shows how much lubricant you’ll need, depending on the size of the conduit and the length of the pull.
9. Can Petroflex provide Cable-In-Conduit?
Yes, we SPECIALIZE in the installation of all types of cable in conduit. We stock many cable sizes/types installed in duct, but can also install your FOC, AL or Cu primary or secondary cable, or PV cable to meet your job specifications. Call 1-800-433-5711 with your cable requirements for engineering expertise and see CableGuard™ page for more information.
10. Is selective back fill required when using polyethylene conduit?
Selective back fill is not required with polyethylene. PVC, on the other hand, is not flexible, and can be damaged by rocks and other debris. Polyethylene is much more forgiving.
11. What standards does Petroflex’s polyethylene conduit meet?
Petroflex manufactures to ASTM D2447, ASTM D3035, ASTM D3485, ASTM D2239 and NEMA TC7 specifications. We are also listed and accepted by Underwriter’s Laboratories (UL), MSHA, most DOT’s, and all major telecommunications companies.
12. Is polyethylene REA-approved?
The REA (Rural Electrification Administration) is now the RUS (Rural Utilities Service). The RUS does not issue an “approved” or “unapproved” list for conduit. However, our Petroflex conduit and API pedestals are accepted by RUS and are RUS listed. Click here to view our RUS acceptance letters
13. Is polyethylene ultraviolet resistant?
Yes, polyethylene is UV resistant. Black conduit has the best UV resistance of any color, because the UV rays cannot penetrate the plastic. For above-ground installations, we recommend using only black conduit. Petroflex’s color conduit contains UV stabilizers and is guaranteed to be UV resistant in direct sunlight for one year.
Fire retardant polyethylene is not UV resistant due to the absence of UV inhibitors. Therefore, we recommend that fire retardant polyethylene not be exposed to direct sunlight.
14. How well does polyethylene function in extreme weather conditions?
We have seen polyethylene conduit installations continue, even when temperatures dropped down to 0 degrees F (17.8 degrees C). Polyethylene works well in extreme hot or cold, even when outside temperatures are -50 degrees F (-45.6 degrees C).
15. What is the difference between polyethylene and PVC?
Durability and flexibility gives polyethylene the edge over PVC (polyvinyl chloride). PVC is extremely rigid, inflexible and has cold weather restrictions. Plus, PVC has to be glued every ten to twenty feet, increasing installation labor and material costs.
HDPE is a compound whereas PVC is a mixture, thereby providing the same quality from batch to batch. Ground shifting does not crack HDPE as it does PVC. HDPE is much more resistant to acids, alkali and hydrocarbons than PVC.
16. Why should I use polyethylene when PVC has a lower cost per foot?
PVC may cost less per foot, but you’re only talking about the conduit. Add increased labor and material costs for all the extra connections to the PVC price, and you’ll see that polyethylene actually costs less in the ground.
17. What kind of flexibility and bend radius can I expect when using polyethylene?
Polyethylene’s flexibility means easier installations, with less bends and elbows, and that adds up to faster installations. Here is an easy way to remember flexibility and bend radius – it’s approximately ten times the outside diameter of the conduit.
18. Is polyethylene available in continuous lengths?
Petroflex manufactures a variety of standard sizes and lengths, from ten feet to five thousand continuous feet lengths. Since Petroflex is a custom extrusion manufacturer, we can manufacture special lengths whenever you need them.